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Postings from June 2003
Hi! Arrays are confusing me and I don't know why. I feel that I understand it but the test questions in Learning Perl for Win32 is tripping me up. For example, here's #2 below with the answer and explanation: 2. Write a program that reads a number and then a list of strings (all on separate lines), and then prints one of the lines from the list as selected by the number. One way to do this is: print "Enter the line number: "; chomp($a = <STDIN>); print "Enter the lines, end with ^Z:\n"; @b = <STDIN>; print "Answer: $b[$a-1]"; The first line prompts for a number, reads it from standard input, and removes that pesky newline. The second line asks for a list of strings, then uses the <STDIN> operator in a list context to read all of the lines until end-of-file into an array variable. The final statement prints the answer, using an array reference to select the proper line. Note that we don't have to add a newline to the end of this string, because the line selected from the @b array still has its newline ending. You'll need to type CTRL-Z at the console to indicate an end-of-file. I'm confused on the [$a-1] part of the last line. Why not $b[$a] instead? Also, are there any notes online for this book or summaries? I've made notes from the book but I'm still not able to compartmentalize how to use arrays (I feel that I do but I'm getting screwed by these test questions!! I've moved on to other chapters but they're nailing me also. ARGH!!!). Thanks! :-)Thread Next